# Classifications

### Classification Basics

Classifications group and classify BIM data simply and efficiently. In addition to the standard IFC classification according to the IFC classes, there are various classification systems available. The most commonly used are: 

1. MasterFormat | A master list for organizing construction work results, requirements, products, and activities. Mostly used in bidding and specifications, MasterFormat originated in North America and is produced by the Construction Specifications Institute (CSI) and Construction Specifications Canada (CSC).
2. UniFormat | For arranging construction information, organized around the physical parts of a facility known as functional elements, and mainly used for cost estimates. UniFormat originated in North America and is produced by the Construction Specifications Institute (CSI) and Construction Specifications Canada (CSC).
3. Uniclass | For all aspects of the design and construction process. In particular, for organizing library materials and structuring product literature and project information. Uniclass originated in the United Kingdom and is produced by the Construction Industry Project Information Committee (CPIC) and the National Building Specification (NBS).
4. OmniClass | For organization, sorting, and retrieval of product information for all objects in the built environment in the project lifecycle. OmniClass originated in North America and is produced by the Construction Specifications Institute (CSI) and Construction Specifications Canada (CSC).

More detailed information about the classification systems can be found in the Whitepaper available at [https://interoperability.autodesk.com](https://interoperability.autodesk.com/)

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### UniFormat (Assembly Code)

The default classification system used in Revit is the Uniformat system. It is included as a text file with the Revit installation: 

C:\ProgramData\Autodesk\RVT  20XX\Libraries\\\<your  localization>\UniformatClassifications.txt

<figure><img src="/files/YIowD14RLUkwDHKwV7tt" alt=""><figcaption><p>Assembly Code Settings in Revit can be found under: Manage -> Additional Settings -> Assembly Code</p></figcaption></figure>

The UniFormat classification is assigned to the *Assembly Code* parameter and is automatically exported as [IFCClassification](https://standards.buildingsmart.org/IFC/RELEASE/IFC4_1/FINAL/HTML/schema/ifcexternalreferenceresource/lexical/ifcclassification.htm):

<figure><img src="/files/eifHBLSJUEG2saiaDIu0" alt=""><figcaption><p>Assembly Code assignment in Revit and export to IFC</p></figcaption></figure>

### Masterformat (Keynotes)

Keynotes in Revit are actually meant for annotating the Revit elements and are based on the MasterFormat by default and can be used for classification purposes as well. \
The classification (RevitKeynotes.txt) is included in the Revit library and can be found here:&#x20;

C:\ProgramData\Autodesk\RVT 20xx\Libraries\\\<your locale>

<figure><img src="/files/9SHgfdGwADIBDU7XEIW4" alt=""><figcaption><p>Keynote Settings can be found under: Annotate > Keynote > Keynoting Settings</p></figcaption></figure>

<figure><img src="/files/OyA1qXTdoBgdFvFVlvK0" alt=""><figcaption><p>Assigning Keynotes in Revit</p></figcaption></figure>

### OmniClass&#x20;

Omniclass is by the third classification system included in Revit by default, however it is only available for loadable families by default. For a full use of this classification, it is recommended to use the Standardized Data Tool for Revit.&#x20;

The classification file shipped with Revit can be found here:&#x20;

*C:\Users\\\<current username>\AppData\Roaming\Autodesk\Revit\\\<product name and release>*

For correctly exporting the Omniclass classification to IFC, it should be set manually under *Modify Setup -> Property Sets -> Classification Settings*:

<figure><img src="/files/p5YvFIFg1dvvpuHiZKeH" alt=""><figcaption></figcaption></figure>

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